1. Field of the Invention
The present invention relates in general to an apparatus and method for recovering plastic from commingled plastic and paper fiber waste and other contaminants, and more specifically is directed to a method and apparatus involving the application of a turbulent flow of air against the contaminated plastic to provide separation.
2. Description of the Prior Art
With the wide use of plastic materials, such as polyethylene, that are used in conjunction with a variety of different types of paper fibers or other contaminants, a large amount of commingled plastic and fiber waste is produced on an annual basis throughout the world. Such waste materials include agricultural film, material from paper recycling plants and post consumer plastic such as grocery and garbage bags.
The separation of contaminants from such plastic materials is often difficult because the materials are contaminated with types of fibers that are similar in size and weight to the plastic sought to be reclaimed. Thus, a number of apparatus and methods have been developed for the reclamation of plastic from such materials. For example, see U.S. Pat. No. 6,149,012 issued to Brooks, et al.; U.S. Pat. No. 5,255,859 issued to Peacock, et al.; U.S. Pat. No. 5,540,244 issued to Brooks, et al.; U.S. Pat. No. 5,277,758 issued to Brooks, et al.; U.S. Pat. No. 5,110,055 issued to Teeny; U.S. Pat. No. 5,084,1.35 issued to Brooks, et al.; U.S. Pat. No. 5,174,316 issued to Keller, et al.; U.S. Pat. No. 5,908,165 issued to Guschall, et al. and U.S. Pat. No. 5,335,786 issued to Roberto.
One of the most common methods of reclaiming plastic that has been contaminated with fibers is through the use of a water tank in which the contaminated plastic is placed. Because paper fibers readily absorb water they tend to sink in the tanks whereas the polyethylene plastic scrap will float and can be skimmed from the top. However, such water tank processes suffer from the disadvantage of relatively high operating costs necessitated by the use of the water tanks and the time involved in performing them.
U.S. Pat. No. 6,149,012 issued to Brooks, et al. has recognized these difficulties and provides a dry system and method for cleaning and recovering plastic from coated fiber poly waste. The system and method disclosed in such patent involves the use of shredding, screening, magnetic separation and cyclone separation equipment in combination with densification and agglomeration of the plastic/paper material. Although such system seems to be an improvement from the use of water separation tanks, the efficiency of the disclosed system and method appears to be less than desired. Accordingly, the present invention was designed as an improvement over the above described prior art systems to provide an efficient and effective method and apparatus for the removal of contaminants from plastic material.